Mechanistic studies of the eneallene-eneyne[3,3]sigmatropic rearrangement are planned. The kinetics and stereochemistry will be explored in detail in order to search for the putative 1,4-biradical intermediate resulting from cyclization in the first step of a cyclization-cleavage mechanism. The stereochemistry of the intramolecular ene cyclization of eneallenes will be determined. The role of orbital overlap in controlling the stereochemical course of the homodienyl and bis-homodienyl hydrogen shift will be explored. A major objective is the development of a method for transfer of chirality with efficiencies of a million-to-one or better. The health relatedness of the project derives from its impact on methods for the synthesis of medicinally important natural and artificial substances, including drugs, hormones, alkaloids, and other materials.